Allow the cvs2svn tests to be run in tarball distributions:
Allow the cvs2svn tests to be run in tarball distributions:

* tools/cvs2svn/run-tests.py: Use a better way of checking that we're
    in the right directory, and do it before path-dependent imports.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion